Serious mental illness has become so prevalent in the US corrections system that jails and prisons are now commonly called “the new asylums.” In point of fact, the Los Angeles County Jail, Chicago’s Cook County Jail, or the New York’s Riker’s Island Jail Complex each hold more mentally ill inmates than any remaining psychiatric hospital in the United States. Overall, approximately 20% of inmates in jails and 15% of inmates in state prisons are now estimated to have a serious mental illness. Based on the total inmate population, this means approximately 383,000 individuals with the severe psychiatric disease were behind bars in the United States in 2014 or nearly 10 times the number of patients remaining in the nation’s state hospitals.

In 44 states, a jail or prison holds more mentally ill individuals than the largest remaining state psychiatric hospital; in every county in the United States with both a county jail and a county psychiatric facility, more seriously mentally ill individuals are incarcerated than hospitalized http://www.treatmentadvocacycenter.org/storage/documents/backgrounders/smi-in-jails-and-prisons.pdf

Prisons were not meant to be hospitals, but if these people are not treated, then they will commit a crime and become part of the swinging door. TYhis problem is not limited to the Unites states, it is worldwide, but has yet to be addressed on a world scale.

A recent study in the United Kingdom

“There are more than 10 million individuals in prison at any given time with more than 30 million circulating through each year. Research has consistently shown that prisoners have high rates of psychiatric disorders, and in some countries, there are more people with severe mental illness in prisons than psychiatric hospitals. Despite the high level of need, these disorders are frequently underdiagnosed and poorly treated. In this structured review, we provide an overview of the epidemiology of psychiatric disorders in prison, summarize information on rates of suicide and violence victimization and risk factors for these outcomes, and outlined evidence-based interventions for mental health. Based on this, we propose a series of clinical, research, and policy recommendations. The aim is to provide a broad synthesis of the main issues relating to the mental health of adult prisoners and highlight gaps in evidence and practice. Two special populations are briefly discussed, namely women and older adults. Juveniles in prison have distinct mental health needs, and an overview of these is outside the scope of this review.

In this review, we have used the terms jails and prisons interchangeably and include those who have received a criminal sentence and are detained pretrial (but not individuals in police custody or detained for non-criminal reasons, such as immigration centers). Lancet Psychiatry. 2016 Sep; 3(9): 871–881.
Published online 2016 Jul 14. doi: 10.1016/S2215-0366(16)30142-0